PREFACE. 
T HIS Volume covers the first portion of the Passeriformes, and the notice- 
able feature is its smaller size, compared with some of the preceding 
volumes. I would point out that this decrease in size is not due to any 
attempt to restrict matter, but is mainly because so little has been published 
in detail concerning the birds here treated. This is not altogether on account 
of the rarity of the species, but in some cases through their comparative 
plenitude. In the preface to the last volume, I pointed out that the life-history 
of Australian birds needed most attention, and I would here once again 
emphasize this item. It is possible that distinctions in habits occur in closely 
allied species, and as a novel field for intensive study I would proffer the 
“ Gerygone ” forms or Flyeaters, especially the species classed in Ethelornis. 
It is almost impossible to determine the exact relationships of these forms 
without a good knowledge of their habits, songs, etc., which at present is not 
on record. 
A noticeable feature of the revival of ornithological study is the recent 
description of novel subspecies by local workers, symbolic of increased interest 
in geographical variation. It seems necessary to emphasize the need of 
anatomical investigation of every species, as one of my reviewers has recently 
misunderstood my views. It is very important that a complete anatomical 
knowledge of every form be made known, and no one is more impressed with 
our lack of such information than myself. Yet while we are comparatively 
ignorant on the subject, insignificant items have been given great degree, and 
the higher classification based on variable anatomical details of little import. 
The reviewer wrote : “We find just as much divergence in external characters 
among species which we feel sure must be closely aliied.” It is tb\is claim to 
“ surety ” which I wish to see dispelled, and I want to see anatomical research 
follow the lines of phylogenetic development, and when we have a group of 
closely allied species whose evolution as to superficies is known, their morpho- 
logy should be contrasted and the degree of anatomical variation determined. 
I am now engaged upon the elucidation of morphological features, and I hope 
to use these in conjunction with superficial items to correct and improve the 
present classification. As to subspecies, these are of great value in the 
recognition of geographical limits, and when these are known the coefficient 
of variation in a species as to environmental stresses can be better gauged. 
xi 
